1. Field of Invention
The present invention relates to a multi-mode communication device in the field of wireless communication technology, in particularly to a multi-mode coexistence method of the multi-mode communication device.
2. Description of Prior Art
In the field of wireless communication, signals are modulated in various modulation modes and transmitted via different or same frequency domains in order to realize voice and digital communication. So far, a variety of networks have been constructed, such as GSM/GPRS (Global System for Mobile Communication/General Packet Radio Service) networks and CDMA (Code Division Multiple Access) networks, each of which is highly popularized and takes a large coverage, WLAN(Wireless Local Area Network) which provides a much higher transmission data rate, shorter transmission distance and much lower cost, Bluetooth with the shortest transmission distance to replace a cable function, and so on. During a considerably long term, these communication modes will coexist and provide their own advantages since they have been bringing different convenience and benefit to users in terms of voice, wireless office, VoIP (Voice on IP) and the like. Accordingly, the evolution of the communication device is also oriented towards a so called multi-mode communication device which supports multiple modes simultaneously.
Mutual interference between different modes of signals is always incurred while these signals are traveling on the air simultaneously. Such interference becomes rather severe especially with respect to modes utilizing the same frequency domain. Even in modes using different frequency domains, the out-of-band spurs of signals in one mode probably impose some interference on signals in another mode. In practical applications, the interference between multi-mode signals leads to degradation of voice communication quality, reduction of data transmission rate and even congestion to normal communication, and thus has a strong impact on the reliability and practicability of a communication system. Therefore, multi-mode communication devices are confronted with the problem of multi-mode coexistence.
Currently, most of multi-mode coexistence methods in various communication modes are to evade any interfered channel by means of frequency hopping, such as adaptive frequency hopping, channel retrieval and the like. In such frequency hopping method, the communication device is required to first receive signals on an interfered channel, then analyze and decide the quality and properties of the signals and finally determine whether to effect frequency hopping on this channel. In this way, the requirement on the corresponding reception system is very strict. Even thought a high-performance reception system is adopted, the communication device may hardly carry out a normal operation when exposed to strong interference.
US patent application publication no. US 20040137849 discloses a method for evading an interfered channel by use of frequency hopping, in which, with its reception system being renovated, a communication device first analyzes the frequency interference range of the received signal, obtains a hop sequence for evading the interference signal and then performs frequency hopping. This method necessities a complex renovation of the reception system in the existing communication device, leading to difficult implementation and costly application.